Surgery for Atrial Fibrillation Seoul National University ...
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  • Two dimensional representation of original maze I procedure

Surgery for Atrial Fibrillation Seoul National University ... Surgery for Atrial Fibrillation Seoul National University ... Presentation Transcript

  • Surgery for Atrial Fibrillation Seoul National University Hospital Department of Thoracic & Cardiovascular Surgery
  • Mechanisms of Atrial Fibrillation
    • Etiology
    • Incompletely understood pathogenesis.
    • Ectopic foci, single circuit reentry, multiple circuit reentry have
    • been implicated in initiating and maintaining the condition
    • Prerequisite ; substrate & trigger
    • 1. Substrate is an atrial abnormality, frequently inflammation or
    • fibrosis causes atrial electrical dysfunction that favors
    • development of AF
    • 2. Triggers include atrial ectopic foci, changes in atrial wall tension,
    • and alterations in autonomic tone
    • 3. Although substrate & trigger may vary, evidence points to the
    • primary importance of pulmonary veins and left atrium initiating
    • & maintaining
  • Origin of Atrial Fibrillation
    • Paroxysmal AF Originates from ectopic beats in the pulmonary veins in 94% of cases .
    • This likely relates to the anatomic transition from pulmonary vein endothelium to left atrial endocardium ; at this junction, two types of tissue with different electrical properties are juxtaposed and this may potentiate development of AF.
    • Although there is the critical importance of pulmonary vein in patients with paroxysmal AF, it may not apply to persistent or permanent AF.
    • As regards persistent & permanent AF Direct evidence is lacking , but clinical experience implicates the posterior left atrium & possibly the pulmonary veins in their pathogenesis and maintenance .
    • And in most patients, the left atrium acted as the electrical driving chamber
  • Intermittent Atrial Fibrillation
    • Induction of atrial fibrillation by a premature atrial beat originating in the orifice of one of the pulmonary veins
  • Intermittent Atrial Fibrillation
    • Once induced, all atrial fibrillation is characterized by the presence of multiple macroreentrant circuits in the atria.
  • Intermittent Atrial Fibrillation
    • Trigger for the induction of intermittent atrial fibrillation is located in the pulmonary veins in 90% of patients & outside the pulmonary vein area in 10% of patients .
  • Intermittent Atrial Fibrillation
    • Each subsequent episode of atrial fibrillation requires another premature atrial beat to initiate the episode, with the trigger again being the pulmonary veins in the majority of cases .
  • Re-entry & Implications for AF (Allessie, 1977)
  • Origin of Sinus Tachycardia Impulses
  • Atrial Fibrillation
  • Clinical Significance of AF
    • AF affects nearly 1% of the general population, with a striking increased incidence in the elderly.
    • High morbidity & increased mortality rates because of tachycardia-induced cardiomyopathy, hemodynamic compromise, & thromboembolism, causing serious health concern &financial costs.
    • The aims of treatment are resortation of normal sinus rhythm, normal atrial contraction & atrioventricular conduction, rate control, and prevention of thromboembolic complications.
  • Preoperative Assessment for AF
    • Being considered for Maze procedure
    • Evaluation of ventricular function either by echocardiography or contrast ventriculography
    • Coronary angiography for those older than 40 years & with risk factors
    • Concomitant heart diseases should be evaluated
    • Patients with paroxysmal flutter or fibrillation should be evaluated electrophysiologically for AV reentrant circuit
  • Intermittent Atrial Fibrillation Pulmonary Vein Isolation
    • Simple pulmonary vein encirclement will cure 90%. However, 10% of patients with intermittent AF will not be cured with simple pulmonary vein isolation.
  • Continuous Atrial Fibrillation
    • Failure of pulmonary vein isolation in patients with continuous atrial fibrillation
  • Surgery for Cardiac Arrhythmias
    • Isolation procedures do not actually terminate arrhythmias but rather confine them, their trigger mechanisms, or both to a desired region of the heart to minimize their adverse effects.
    • Ablation procedures preclude arrhythmias from developing either by destroying their trigger mechanism or by altering (or removing) the substrate that allows the arrhythmia to be induced and maintained.
  • Surgical Isolation Procedures
    • Elective His bundle ablation for any type of supraventricular tachycardia
    • Left atrial isolation procedure for automatic left atrial tachycardias and atrial fibrillation
    • Right atrial isolation procedure for automatic right atrial tachycardias
    • Corridor procedure for atrial fibrillation
    • Right ventricular isolation procedure for nonischemic ventricular tachycardia
    • Pulmonary vein isolation for the intermittent atrial fibrillation
  • Surgical Ablative Procedures
    • Surgical intervention for the Wolff-Parkinson-White syndrome, which interrupts macroreentrant circuit
    • Discrete cryosurgery for atrioventricular node reentry tachycardia, which interrupts microreentrant circuit
    • Focal cryoablation for automatic atrial tachycardias, which destroys the trigger mechanism
    • Endocardial resection for ischemic ventricular tachycardia, which removes the microreentrant circuit
    • Endocardial cryosurgical procedures for ischemic ventricular tachycardia, which destroys the microreentrant circuit
    • Maze procedure for atrial fibrillation, which destroys macroreentrant circuits
  • Ideal Ablative Procedures
    • Elimination of AF as an arrhythmia
    • Restoration of sinus rhythm
    • Maintenance of AV synchrony
    • Restoration of atrial transport function
    • Elimination of thromboembolic risks
  • Ablative Procedures
    • Ablation for Supraventricular Arrhythmias
    • Right atriofascicular accessory pathways
    • Ebstein’s anomaly
    • Coronary sinus abnormalities
    • Triangle Koch & AV node-His bundle (AVNRT)
    • Atrial tachycardia of ectopic origin
    • Atrial flutter
    • Atrial fibrillation
  • Indications for Maze Procedure
    • Failure of medical therapy as a result of
    • Symptomatic intolerance of the arrhythmia despite phamacologic rate control
    • Inability to achieve satisfactory phamacologic rate control
    • Patient intolerance of requisite drug therapy
    • Occurrence of at least one previous thromboembolic episode
  • Surgical Techniques for AF
    • Cox-Maze III
    • Partial Mazes
    • Radiofrequency
    • Microwave
    • Cryothermy
  • Assessing Results of AF Surgery
    • Permanent AF
    • Detection requires at least 2 EKG examination separated by 7 days or more
    • Data analysis is done after 6 months more because atrial healing and stabilization of rhythm may take up to 6 months after surgery
    • Surgical failure
    • Presence of AF at 6 months or more after operation that is permanent or paroxysmal and unresponsive to antiarrhythmic medication
    • Prevalence of AF
    • Paroxysmal, persistent, or permanent
    • Other events
    • Stroke, pacemaker implantation(sick sinus syndrome), atrial dysfunction(atrial activity)
  • Map of Maze I Procedure
    • Two dimensional original maze I procedure
  • Map of Maze II Procedure
  • Map of Maze III Procedure
  • Maze III Procedure
  • Maze III Procedure
  • Maze III Procedure
  • Maze III Procedure
  • Maze III Procedure
  • Maze III Procedure
  • Maze III Procedure
  • Maze III Procedure
  • Maze III Procedure
  • Standard Maze III Procedure
    • The 5 left atrial lesions of the standard maze III
    • surgical procedure for atrial fibrillation.
  • Mini-Maze Procedure for AF
    • Pulmonary vein encircling incision, left atrial isthmus lesion with coronary sinus lesion, & right atrial isthmus lesion
  • Postoperative Complications
    • Atrial dysrhythmias, flutter & fibrillation
    • Sinus node dysfunction
    • Blunted tachycardia response to exercise
    • Absence of detectable sinus activity
    • Complete heart block
    • Early postoperative fluid retention
    • Postoperative pericardial effusion
  • Results of Surgery for AF
    • Cox-Maze III
    • 1. Late freedom from AF is around 90% (Cox group;98%)
    • 2. Temporary postoperative AF is common(30~40%) due to
    • shortened atrial refractory period & did not diminish
    • longterm results(return sinus rhythm over ensuing 3 months)
    • 3. 15% require new pacemaker therapy
    • 4. Atrial transport function in 98%(Rt),93%(Lt)
    • Partial Mazes
    • 1. Restore sinus rhythm around 80%
    • 2. Increased risk of atrial flutter, usually right origin(5~10%)
    • 3. Radial incision approach provides results comparable to
    • those of Cox-Maze III
    • 4. More effective restoration of atrial transport function
  • Results of Surgical Treatment
    • Cox-Maze procedure: Cox & Colleagues
    • @ Among 346, 2% op.mortality, AF was cured in 99%, 2%
    • required long-term postoperative antiarrhythmic medication
    • @ Successful ablation was unaffected by presence of mitral valve
    • disease, LA size, type of AF
    • @ Temporary postoperative AF in 38%
    • @ New pacemaker was required in 15%
    • @ RA transport function in 98%, LA transport function in 93%
    • 2. Cox-Maze III: Other centers
    • @ Around 90% of late freedom from AF Cured AF in 75-82%
    • in most series of mitralvalve surgery+ Cox-Maze III
    • @ Amplitude of the AF wave and diameter of the LA :
    • independent predictors of sinus restoration after operation
  • Coexistence of Sinus Rhythm & Segmental Atrial Fibrillation after Maze
  • Partial Maze Procedures
    • “ Simple left atrial procedure” (Sueda et al. 1996)
    • “ Partial Maze procedure” (Takami et al. 1999)
    • “ Mini-Maze” (Szalay et al. 1999)
    • More simplified, take less time, use alternative
    • energy sources
    • Include some of the incisions and cryoablation lesions of the Cox-Maze III, but not all
    • Focus on the left atrium, including PVI, LAA excision or exclusion
  • Energy Sources for Ablation
    • Radiofrequency
    • Alternating current of 350 KHz to 1 MHz to heat the tissue
    • Heating tissue for approximately 1 minute at 70~80C produces
    • lesions 3 to 6 mm deep to create a transmural line of conduction
    • block by tissue vaporization and surface cooling
    • Microwave
    • Thermal damage & subsequent scar formation , by high-frequency
    • electromagnetic radiation(microwave) causes oscillation of water
    • molecules in tissues, converting electromagnetic energy into kinetic
    • energy(heat)
    • Depth & volume of heated tissue are greater than radiofrequency,
    • and not char the endocardial surface
    • Cryothermy
    • Application of nitrous oxide-based cryoprobe to atrial tissue for 2
    • minutes at -60C produces a transmural lesions , leaving a smooth
    • endocardial surface
  • Radiofrequency (RF)
    • Uses alternating current of 350kHz to 1 MHz to heat tissue
    • Experimental data : 1min at 70-80°C produces 3-6mm deep lesions
    • Unipolar vs. bipolar system
    • Dry vs. SIRFMM
    • Multiple RF systems : long flexible, rigid, pencil-like probes with a cool tip, bipolar clamp
    • Either epicardial or endocardial ablation
    • Time : 10-20 min for creation of left-sided lesion sets vs. 1hr. for Cox-Maze procedure
  • Surgical Techniques for RF
  • Radiofrequency Ablation
  • Bipolar RF
  • Microwave
    • Interest is growing in microwave energy
    • High-frequency electromagnetic radiation causes oscillation of water molecules in tissue, converting elctromagnetic energy into kinetic energy (heat).
    • Depth and the volume of heated tissue are greater, resulting in a higher probability of transmural lesions
    • No char, which may reduce risk of thromboembolism
    • Shielded probes produce safe epicardial ablation
    • Available probes : 2-,4-,10 cm
    • Energy set at 65W, 45 second application time
    • (Gillinov AM et al. Ann Thorac Surg 2002;74:1259-61)
  • Microwave System
    • The FLEX 2™, FLEX 4™ and FLEX 10™ Microwave Ablation Probes are sterile, single-use, hand-held, surgical devices used exclusively with the AFx Microwave Generator
  • Cryothermy
    • Well-established modality in arrhythmia surgery and an important component of the Maze III
    • Nitrous oxide-based cryoprobe
    • 2min at -60°C reliably produces a transmural lesion that can be confirmed visually
    • Tissue architecture is preserved, leaving a smooth endocardial surface
    • No flexible probe till now
  • Transmurality & Damaging Effect
    • Discontinuous line allow AF breakthrough or potentiate development of atrial flutter
    • Ensured transmurality : cut and sew, endocardial cryothermy, bipolar RF by measuring changes in tissue impedence
    • Unipolar RF, epicardial cryothermy on a beating heart do not guarantee transmural lesions
    • Esophageal injury has been reported
    • Thermal energy application should be avoided in thin, frail patients with delicate tissues
  • Results of Partial Mazes
    • Approximately 80% of patients restored
    • sinus rhythm
    • Minor variations in incision pattern and
    • cryolesions do not influence the results
    • Occurrence of atrial flutter is 5-10%
  • Results of Radiofrequency Ablations
    • Most series : mitral valve surgery + RF
    • 70-80% of successful ablation
    • Up to 60% of perioperative AF
    • 30-40% of AF at discharge, but many return
    • to sinus rhythm over 3 months
    • Atrial transport function in 80-100% who
    • return to sinus rhythm
  • Results of Microwave Ablations
    • Long-term results are unavailable; microwave catheter has only recently become available for intraoperative treatment of AF
    • Among 10 patients. who had mitral valve operations + MW of the pulmonary veins, 6 in NSR, 3 in AF, 1 under pacing at discharge
    • Approximately 80% of patients can be cured of AF
  • Energy Sources for Ablation
    • Type Endocardial Epicardial Flexible Assess No char Rapid
    • application application probe transmural
    • Radiofreq. + + + + - +
    • Microwave + + + - + +
    • Cryothermy + + - - + -
    • * Radiofrequency energy may be delivered in unipolar or bipolar fashion
  • Surgical Option for Atrial Fibrillation
    • Left atrial incisions of Cox-Maze III procedure
  • Surgical Option for Atrial Fibrillation
    • Left atrial part of standard Cox-Maze procedure
  • Cox-Maze Procedure
    • A; Cox maze III procedure
    • B; Kosakai maze procedure
    • C; Cryomaze procedure
  • Modifications of Maze Procedure
    • * Right & left atrium seen
    • from behind(A) & inside(B)
    • * Crossed lines;
    • modified atriotomies
    • * Dotted area; cryoablation
    • * Thick lines; SA node artery
    • * Right, left, posterior sinus node
    • arteries
  • Modifications of Cox-Maze III
    • A; Modified procedure
    • B; Incision lines & impulse propagation
    • after modified procedure
  • Modifications of Cox-Maze III
    • A ; conventional Cox-Maze
    • B & C ; modification(usual & large atrium)
    • Crossed lines ; surgical atriotomies
    • Thick black lines ; cryoablation
  • Radiofrequency Modified Maze
    • A; Lines of electrical activation
    • B; Zigzag lines depicting incision in the atria
    • C; Dotted lines depicting endocardial ablation
  • Radiofrequency Maze Procedure Right-sided Saline Irrigated
    • A ; RA appendage excised
    • B ; Vertical incision
    • C ; Second longitudinal incision in RA
    • D ; Ablation line is created between cannulation
  • Radiofrequency Maze-Berlin Modification
    • The incisions & sutures of the standard maze technique are replaced by radiofrequency ablation lines(dashed lines)
  • Radiofrequency Maze-Berlin Modification
    • Dashed lines show position of radiofrequency maze lines of Berlin modification in comparison to the standard maze lines
  • AF Surgery Simplified with Cryoablation To Improve LA Function(I)
    • Redundant, enlarged LA resected
    • i; incision to atrioventricular groove, j; cryoablation of coronary sinus
  • AF Surgery Simplified with Cryoablation To Improve LA Function(II)
    • A; Anterior view of posterior left atrial wall
    • B; Posterior view of left & right heart
    • Cryoablation indicated by dotted lines
  • Bilateral Appendage-Preserving Maze
    • A; Diagram of BAP-Maze procedure
    • B; Impulse propagation pattern
    • C; Diagram of Maze III
  • Radial Approach for Atrial Fibrillation
    • Small circle indicates SA node, & shaded area indicates the isolated portion of the atrium
    • Arrows indicate the activation wavefront from the SA node, radiating toward the annular margins
  • Radial Approach for Atrial Fibrillation
    • Thick lines ; surgical incisions
    • Solid area ; atria surgically isolated or excised
    • Dashed lines ; Bachmann’s bundle between appendage, septum, and crista terminalis
    • Arrows ; activation sequence
  • Radial Approach for Atrial Fibrillation
    • Maze procedure. Radial approach
  • MVR with Maze III
    • A & B ; Left side incisions
  • MVR with Maze III
    • Right side incisions, Maze III procedure
  • MVR with Maze III
  • Reduction Plasty with Maze
  • Reduction Plasty with Maze
  • Atrial Endocardial Maps after Maze
    • The shaded area denotes electrically isolated region